With the advent of Heterogeneous Network (HetNet), Ultra Dense Network (UDN) and a Device-to-Device Communication (D2D) communication mode, network architecture is capable of providing a multi-layer coverage mode as compared with a traditional cellular network where a single-layer coverage mode is provided. A radius of a cell coverage becomes smaller and smaller, so there is a large challenge in inter-cell interference and mobility. Ring & Young initially raised the concept of cellular network. In a traditional cellular system, each base station merely covers a limited region, i.e., a cell, due to the limitation of transmission power. The base station is just a control and data center for the cell, and it takes charge of radio resource management, signal processing and mobility management within the coverage thereof. Due to the existence of inter-cell interference and coverage black hole, it is impossible for this network deployment mode to provide excellent system performance. Through a centralized or coordinated processing mode among a plurality of base stations, such techniques as Distributed Antenna System (DAS) and Coordinated Multiple Point (CoMP) have started to change the concept of “cellular” with a single base station as a management center. For hyper cellular architecture (Business Communication Group (BCG)) defined by Greentouch and dual-connection defined by the 3rd Generation Partnership Project (3GPP), signaling and data for each base station are separated from each other. In order to achieve uplink/downlink decoupling of traffic offload in the HetNet in a better manner, the traditional concept of “cellular” has been further broken through.
Due to the emergence of a mobile network, such businesses as on-line video streams, video conferences and interactive games have been deployed on a large scale, resulting in a huge number of network traffic. Especially at a densely urbanized region or a hotspot region, the mobile communication network has confronted with an explosion of the data traffic. Currently, one feasible scheme for solving the problem in the explosion of the data traffic is to reduce a coverage area of the cell and increase the number of the deployed cells, so as to increase the frequency multiplexing as well as the capacity. The 3GPP has proposed a scheme for increasing the network capacity through the deployment of Femtocell, Picocell and Microcell, so as to achieve the traffic offload. Small cell enhancement technique is a feature of the 3GPP. Mobile and wireless communications Enablers for the Twenty-twenty Information Society (METIS) has proposed the concept of “UDN”, studied the use of context information to optimize the selection of access points by a User Equipment (UE), and analyzed the provision of the services for the UE through a cell cluster, so as to improve the mobility by reducing unnecessary handover operations and reducing handover operations within a small region.
Currently, the UE is provided with the data services mainly in a network-centered manner, and the UE needs to acquire a network environment and trigger the handover operation through detecting a signal. In the case of network-intensive deployment, there are various APs for a Multi Radio Access Technology (Multi-RAT), and the coverage area is reduced. Due to the dynamic change of the APs, the UE needs to perform the handover operation frequently even when the UE moves at a low speed or even in a stationary state. At this time, the UE needs to acquire the network environment at any time so as to perform the handover operation, thereby the user experience may be seriously adversely affected. In addition, the frequent handover operation may result in the signaling load for a core network.
A current cell cluster mechanism is mainly used for resource scheduling and allocation. Most of the cell clusters are predefined. Through providing the services to the UE using the cell clusters, it is able to reduce the number of the handover operations made by the UE. In the UDN, each AP may be accessed dynamically in accordance with the load of the network and the energy-saving requirement. The UE may serve as an AP for providing the services to the other UEs. The diversity of the user requirements results in different bandwidths for the UEs, so it is necessary to perform coordination between multiple layers of the network, so as to provide the services to the UE. In this regard, through the cell clusters in a stationary state, it is impossible to dynamically add the new APs into a service list, thereby it is adverse to the provision of continuous services to the UE. In addition, it is also adverse to the coordination among different RATs through the cell cluster mechanism in the traditional network, so it is impossible for a future network system to provide optimum services to the UE.